基于空间谱的多天线盲频谱感知算法

Spatial spectrum based blind spectrum sensing for multi-antenna cognitive radio system

现有的频谱感知算法主要在时间、频率以及地理空间维度进行检测,对角度维的利用尚不成熟。将多天线技术中的到达角(AOA,angle of arrival)估计算法应用到频谱感知领域,提出了2种基于空间谱的盲频谱感知算法,分别为最大—最小延迟相加谱值比检测和平均—最小延迟相加谱值比检测。利用空域匹配滤波的优势,新算法在低信噪比下得到了较高的检测概率,同时为角度维的频谱接入提供了AOA信息,从而提高了频谱利用率。此外,运用随机矩阵理论,推导了检测阈值和检测概率的理论值。仿真结果表明,在Nakagami-m信道下,提出的算法具有比现有盲感知算法更优的检测性能。

State-of-the-art sensing methods only exploit three dimensions of the spectrum space： frequency, time and space whereas the angle dimension has not been exploited well enough for opportunistic spectrum access. Motivated by this, the authors apply angle of arrival （AOA） estimation algorithm to spectrum sensing and propose two blind spectrum sensing methods based on spatial spectrum. First is based on the ratio of maximum to minimum delay-sum spatial spec- trum; the other is based on the ratio of average to minimum delay-sum spatial spectrum. Taking the advantage of spatial matched filtering, the proposed methods can achieve high probability of detection as well as offer the AOA information for spectrum access, which improve the spectrum efficiency. In addition, utilizing latest random matrix theories （RMT）, this work quantifies the detection threshold and derives the probabilities of detection for the proposed methods in theory. Extensive simulations carded out in Nakagami-m fading channel indicate that the proposed methods outperform the ex- isting blind spectrum sensing methods.